Infective Endocarditis¶
Chapter 133 | Part 5: Infectious Diseases · Part 5 – Infectious Diseases: Bacterial · Chapter 133
Key Clinical Points¶
- Infective endocarditis (IE) is a mass of platelets, fibrin, microorganisms, and scant inflammatory cells on heart valves or other endocardial surfaces.
- Acute IE is characterized by rapid progression, high fever, and significant structural damage; Subacute IE follows an indolent course with slower damage.
- Staphylococcus aureus is the most common bacterial cause of IE in developed countries.
- The Duke-ISCVID Criteria are the gold standard for diagnosis (Definite: 2 major, or 1 major + 3 minor, or 5 minor).
- TTE has lower sensitivity (65–70%) compared to TEE (>90%) for detecting vegetations.
- S. aureus bacteremia carries a high risk of IE and mortality; routine echocardiography is mandatory.
- IE is rejected if an alternative diagnosis is found, no recurrence occurs after <4 days of therapy, or no histology is found in surgery/autopsy within 4 days.
- Treatment requires prolonged parenteral antibiotics to penetrate the fibrin-rich vegetation.
- Risk factors have shifted from rheumatic heart disease to IDU, degenerative valve disease, and intracardiac devices.
- Specific embolic risk factors include vegetations >10 mm, mitral valve anterior leaflet involvement, and S. aureus infection.
DEFINITION & CLASSIFICATION¶
• Definition (Harrison's 22e): mass of platelets, fibrin, microorganisms, and scant inflammatory cells on heart valves or other endocardial surfaces. • Location: Most commonly heart valves; also occurs on low-pressure side of VSD, mural endocardium (damaged by jets/foreign bodies), or intracardiac devices. • Infective Endarteritis: The analogous process involving arteriovenous shunts. • Classification by Valve Type: ◦ Native-valve endocarditis (NVE) ◦ Prosthetic-valve infections (PVE) ◦ Infective endocarditis involving cardiovascular implantable electronic devices (CIED-IE) ◦ Transcatheter aortic valve replacement (TAVR)-PVE • Classification by Temporal Evolution: ◦ Acute IE: Rapidly febrile, rapid structural damage, death within weeks if untreated. ◦ Subacute IE: Indolent course, slow structural damage, rarely metastasizes.
EPIDEMIOLOGY¶
• Incidence: ~15 cases per 100,000 population per year in developed countries. • Shifting Risk Factors: Transition from chronic rheumatic heart disease (common in developing nations) to: ◦ Injection drug use ◦ Degenerative valve disease ◦ Intracardiac devices • PVE Risk: Highest during the first year after replacement; higher risk for bioprosthetic valves than mechanical valves.
ETIOLOGY & PATHOPHYSIOLOGY¶
• Primary Pathogen: Staphylococcus aureus is the most common bacterial species in developed countries. • Portal of Entry: ◦ Viridans streptococci: Oral cavity ◦ Staphylococci: Skin ◦ HACEK organisms: Upper respiratory tract ◦ S. gallolyticus: Gastrointestinal tract (associated with colonic polyps/tumors). • Table 133-1 Summary: ◦ Streptococci: 40% of NVE; 13% of HA-associated. ◦ Enterococci: 9% of NVE; 16% of HA-associated. ◦ S. aureus: 52% of HA-PVE; 36% of CIED-IE. ◦ CoNS: 33% of early PVE; 41% of CIED-1E. ◦ HACEK: 3% of NVE; 6% of TAVR PVE. ◦ Gram-negative bacilli: 1% of NVE; 13% of HA-PVE. ◦ Candida spp.: <1% of NVE; 8% of early PVE. • Pathogenesis: ◦ Endothelium is normally resistant to infection. ◦ Injury → formation of platelet-fibrin thrombus (nonbacterial thrombotic endocarditis [NBTE]). ◦ Thrombus serves as a site for bacterial attachment during transient bacteremia. ◦ Adherence factors: Fibronectin-binding proteins (Gram+), clumping factor (S. aureus), fibrinogen-binding surface proteins (Enterococcus), glucans/FimA (Streptococci). ◦ Proliferation → formation of dense microcolonies if resistant to serum/platelet microbicidal activity.
CLINICAL FEATURES¶
• General Manifestations: Result from structural damage, vegetation embolization, hematogenous infection, or immune complex deposition. • Table 133-2 Clinical/Lab Frequency: ◦ Fever: 80–90% ◦ Heart murmur: 80–85% ◦ Anemia: 70–90% ◦ Elevated CRP: 90% ◦ Circulating immune complexes: 65–100% ◦ Splenomegaly: 15–50% ◦ Neurologic manifestations: 20–40% ◦ Peripheral manifestations (Osler's, Janeway, etc.): 2–15%. • Specific Populations: ◦ PWID: 35–60% limited to tricuspid valve; fever with faint/no murmur; no peripheral features. ◦ Tricuspid IE: Associated with septic pulmonary emboli (cough, pleuritic pain, nodular infiltrates). ◦ CIED-IE: May have obvious or cryptic generator pocket infection.
DIFFERENTIAL DIAGNOSIS¶
• Mimickers of Culture-Negative IE: ◦ Atrial myxoma ◦ Marantic endocarditis ◦ Antiphospholipid antibody syndrome • Distinguishing Features: ◦ S. aureus infection often presents with acute features (e.g., septic emboli/subungual hemorrhage).
DIAGNOSTIC APPROACH¶
- Initial Evaluation: Perform clinical, microbiologic, and echocardiographic assessments for patients with IE risk factors or blood cultures showing IE-associated organisms.
- Microbiology (Gold Standard): Multiple blood cultures are required. ◦ Note: 3 cultures from separate sites are recommended but not strictly required.
- Echocardiography Selection (Figure 133-3 Logic): • Pathway A (Low Initial Risk/Low Suspicion):
- Perform TTE → If Positive (+) → Rx.
- If TTE Negative (-) and Low suspicion persists → Look for other source.
- If TTE Negative (-) but suspicion increases during course → Perform TEE. • TEE Positive (+) → Rx. • TEE Negative (-) → Look for other source. • Pathway B (High Initial Risk/Moderate-High Suspicion/Difficult Imaging):
- Perform TEE → If Positive (+) → Rx.
- If TEE Negative (-) and High suspicion persists → Repeat TEE. • Repeat TEE Positive (+) → Rx. • Repeat TEE Negative (-) → Look for other source of symptoms.
- If TEE Negative (-) → Look for other source → Determine if alternative diagnosis established → Clinical judgment regarding treatment. • High-Risk Features: If "high-risk echo features" (large vegetations, valve insufficiency, paravalvular infection, ventricular dysfunction) are present on TTE → Perform TEE for detection of complications.
- Duke-ISCVID Criteria (Table 133-3/11): • Major Criteria:
- Typical organism in ≥2 blood culture sets (e.g., S. aureus, S. lugdunensis, E. faecalis, HACEK, CoNS, etc.).
- Nontypical organisms from ≥3 blood culture sets.
- Positive PCR for Coxiella burnetti, Bartonella spp., or Tropheryma whipplei; OR specific antibody titers (e.g., ≥1:800).
- Echocardiographic evidence of vegetation, perforation, abscess, fistula, or new prosthetic valve dehiscence.
- New valvular regurgitation (requires echocardiographic evidence, not just murmur).
- FDG-PET/CT with abnormal metabolic activity in specific areas.
- Surgical evidence of IE. • Minor Criteria:
- Predisposition (IDU, prosthetic valve, etc.).
- Fever >38.0^{circ}C (100.4^{circ}F).
- Vascular phenomena (emboli, mycotic aneurysm, Janeway lesions, etc.).
- Immunologic phenomena (glomerulonephritis, Osler nodes, Roth spots, positive RF).
- Microbiologic evidence (positive culture from non-endovascular site).
- Imaging criteria (FDG-PET/CT within 3 months of implant).
- Physical exam (New valvular regurgitation on auscultation). • Diagnosis:
- Definite IE: Pathologic evidence OR (2 Major) OR (1 Major + 3 Minor) OR (5 Minor).
- Possible IE: (1 Major + 1 Minor) OR (3 Minor).
- Rejected IE: Does not meet criteria, firm alternative diagnosis, no recurrence after <4 days of therapy, or no evidence on autopsy within 4 days.
- Echocardiography Sensitivity: • TTE: Detects vegetations in 65–70% (Note: some texts say 20–35% fail to detect). • TEE: Detects vegetations in >90%.
MANAGEMENT & TREATMENT¶
- Initial Strategy: • Stable patients with suspected subacute IE → withhold empirical antibiotics initially (especially if treated within last 2 weeks). • Patients with sepsis or deteriorating hemodynamics → initiate empirical treatment immediately after initial blood cultures.
- Antimicrobial Therapy (Table 133-5): • S. aureus: ◦ MSSA: Vancomycin (15–20 mg/kg IV every 6–8 hours) or Daptomycin (8–10 mg/kg daily). ◦ MRSA: Vancomycin (15–20 mg/kg IV every 6–8 hours) or Daptomycin (8–10 mg/kg daily). • Streptococci: ◦ Penicillin-susceptible (incl. S. gallolyticus): Penicillin G (2–3 mU IV q4h) or Ceftriaxone (2 g IV daily). ◦ Moderately resistant: Penicillin G (4–5 mU IV q4h) or Ceftriaxone (2 g IV daily) for 6 weeks. • Enterococcus faecalis: Ampicillin (2 g IV q4h) + Gentamicin (1 mg/kg IV q8h). • HACEK: Ceftriaxone (2 g IV every 12h) or Erythromycin (40 mg/kg/day). • Prosthetic Valve (PVE): ◦ S. aureus: Vancomycin + Rifampin. ◦ Enterococcus: Ampicillin + Gentamicin.
- Surgical Intervention (Table 133-6 & 133-7): • Required for Optimal Outcome:
- Moderate/severe heart failure or shock due to valve dysfunction.
- Paravalvular extension (abscess, fistula, heart block).
- Persistent bacteremia without extracardiac source despite 7–10 days of optimal therapy.
- Lack of effective options (e.g., fungal, Brucella, MDR Gram-negative). • Strongly Considered:
- S. aureus with intracardiac complications.
- Relapse after optimal therapy.
- Large (>10 mm) hypermobile vegetation with significant valve dysfunction.
- Persistent unexplained fever (geq 10 days) in culture-negative IE. • Timing of Surgery:
- Emergent (same day): Valve dysfunction with pulmonary edema/shock; Rupture into pericardial sac; Septal perforation; Paravalvular extension with new conduction changes.
- Elective: Progressive paravalvular regurgitation; Fungal endocarditis; S. aureus with complications; Early PVE (leq 2 months).
COMPLICATIONS & PROGNOSIS¶
• Neurologic Complications: ◦ Cerebrovascular emboli: 15–35% of cases (asymptomatic found in 30–65% of left-sided IE). ◦ Stroke frequency: 8 per 1000 patient-days pre-diagnosis → 4.8 (week 1) → 1.7 (week 2) during effective therapy. ◦ Mycotic aneurysms: Focal dilations at sites of infection in vasa vasorum or where emboli lodge. • Renal & Splenic Complications: ◦ Renal infarcts: Cause flank pain/hematuria; rarely cause dysfunction. ◦ Splenic infarcts/abscess: Manifest as left upper abdominal, pleuritic chest, or left shoulder pain. • Immune Complex Disease: Glomerulonephritis and renal dysfunction (typically improve with antibiotics).
SPECIAL POPULATIONS¶
• People Who Inject Drugs (PWID): ◦ 35–60% limited to tricuspid valve. ◦ Fever, minimal/no murmur, no peripheral features. ◦ Common finding: Septic pulmonary emboli. • Health Care-Associated IE: ◦ Often caused by S. aureus, CoNS, or Enterococci. ◦ Complicates 8–25% of catheter-associated bacteremia.
KEY PEARLS & HIGH-YIELD POINTS¶
• Peripheral Manifestations: ◦ Osler's nodes: Painful, raised, erythematous nodules (fingers/toes). ◦ Janeway lesions: Painless, erythematous macules (palms/soles). ◦ Roth's spots: Retinal hemorrhages with white centers. ◦ Subungual hemorrhages: Petechiae under nails. • Embolic Risk Factors: ◦ Mobile vegetations >10 mm diameter. ◦ Infection of mitral valve anterior leaflet. ◦ S. aureus infection. • Prophylaxis (Table 133-9): ◦ Indicated for: Prosthetic valves/material, LVADs, prior endocarditis, unrepaired cyanotic CHD, and certain valvulopathies after transplant.
Reference Tables¶
TABLE 133-1 Organisms Causing Major Clinical Forms of Infective Endocarditis (IE) ORGANISM(S) Streptococci b…¶
Harrison's 22e, p.1037
| ORGANISM(S) | PROPORTION OF CASES | ||||||
|---|---|---|---|---|---|---|---|
| NATIVE-VALVE IE | PROSTHETIC-VALVE IE AT INDICATED TIME OF ONSET (MONTHS) AFTER VALVE SURGERY |
TAVR PVE | CIED-IE | ||||
| COMMUNITY- ACQUIRED (N = 1718) |
HEALTH CARE– ASSOCIATED (N = 1110) |
<2 (N = 144) | >2-12 (N = 31) | >12 (N = 194) | (N = 295) | (N = 337) | |
| Streptococcib | 40 | 13 | 1 | 10 | 31 | 18 | 2 |
| 2 | — | — | — | — | - | ||
| Enterococcic | 9 | 16 | 8 | 13 | 11 | 24 | 4 |
| 28a | 52d | 22 | 13 | 18 | 23 | ||
| Coagulase-negative staphylococci |
5 | 11 | 33 | 35 | 11 | 20 | 41 |
| 3 | — | — | — | 6 | — | ||
| Gram-negative bacilli | 1 | 1 | 13 | 3 | 6 | 1 | 6 |
| <1 | 1 | 8 | 13 | 1 | 1 | ||
| Polymicrobial/miscellaneous | 3 | 3 | 3 | 6 | 5 | 8 | 2 |
| — | <1 | 6 | — | 3 | |||
| Culture-negative | 9 | 3 | 5 | 7 | 8 | 5 | 6 |
TABLE 133-2 Clinical and Laboratory Features of Infective Endocarditis FEATURE Fever Chills and sweats Anorexia, weight…¶
Harrison's 22e, p.1038
| FEATURE | FREQUENCY, % |
|---|---|
| Fever | 80–90 |
| Anorexia, weight loss, malaise | 25–50 |
| Back pain | 7–15 |
| New/worsened regurgitant murmur | 20–50 |
| Splenomegaly | 15–50 |
| Neurologic manifestations | 20–40 |
| Petechiae | 10–40 |
TABLE 133-3 The Modified Duke Criteria for the Clinical Diagnosis of Infective Endocarditis (IE) a Major Criteria A.…¶
Harrison's 22e, p.1040
- Major Criteria
- A. Microbiologic Criteria
1. Positive blood culture - Microorganism that commonly cause IE in 2 or more separate blood
culture sets (Typical—i.e., S. aureus, S. lugdunensis, E. faecalis,
all streptococcal species except S. pneumoniae and S. pyogenes,
Granulicatella spp., Abiotrophia spp., Gemella spp., HACEK group
organisms and in the setting of intracardiac prosthetic material, CoNS,
C. striatum, C. jeikeium, S. marcescens, P. aeruginosa, C. acnes,
nontuberculosis mycobacteria, Candida spp.)
or
Microorganisms that occasionally or rarely cause IE isolated from 3 or
more separate blood culture sets (Nontypical)
2. Positive laboratory tests - Positive polymerase chain reaction (PCR) for Coxiella burnetti, Bartonella
spp., or Tropheryma whipplei from blood
or
Single blood culture growing C. burnetti or phase I IgG Ab titer ≥ 1:800
or
Indirect immunofluorescence assays (IFA) for IgM Ab and IgG Ab to
B. henselae or B. quintana with IgG Ab titer ≥ 1:800
B. Imaging Criteria
1. Echocardiography or cardiac CT showing vegetation, valvular/leaflet
perforation/aneurysm, abscess, pseudoaneurysm or intracardiac fistula
or
New valvular regurgitation (new/worsening murmur is NOT sufficient;
requires echocardiographic evidence)
or
New prosthetic valve dehiscence/insufficiency
2. FDG-PET/CT with abnormal metabolic activity involving a native or
prosthetic valve, ascending aortic graft, intracardiac device leads, or other
prosthetic material
C. Surgical Criteria
Evidence of IE documented by direct inspection during heart surgery - Minor Criteria
- A. Predisposition: previous history of IE, injection drug use, prosthetic valve,
previous valve repair, congenital heart disease (e.g., bicuspid AV), CIED, more
than mild regurgitation or stenosis, hypertrophic cardiomyopathy
B. Fever: T > 38.0°C (100.4°F)
C. Vascular phenomenon: arterial emboli, septic pulmonary infarcts, mycotic
aneurysm, intracranial hemorrhage, conjunctival hemorrhage, Janeway lesions,
cerebral/splenic abscesses, purulent purpura
D. Immunologic phenomena: glomerulonephritis, Osler nodes, Roth spots,
positive rheumatoid factor
E. Microbiologic evidence: positive blood cultures (not meeting above criteria)
or
Positive culture, PCR, or other nucleic acid-based test for an organism
consistent with IE from a non-endovascular site or single finding of a
skin bacterium by PCR on a valve or wire without additional clinical or
microbiological supporting evidence
F. Imaging criteria: abnormal metabolic activity on FDG-PET/CT within 3 months of
implantation of a prosthetic valve, ascending aortic graft, intracardiac device lead
G. Physical exam criteria: New valvular regurgitation on auscultation - DIAGNOSIS
- Definite IE: 1. Pathologic criteria (microorganisms or active endocarditis identified
in a vegetation/intra-cardiac abscess from cardiac tissue, prosthetic material,
arterial embolus) 2. Clinical criteria (2 major or 1 major + 3 minor or 5 minor)
Possible IE: 1 major + 1 minor or 3 minor
Rejected IE: does not meet above criteria or firm alternative dx or lack of
recurrence with <4 days of antibiotics or no evidence on autopsy
TABLE 133-4 Features Guiding the Need for Echocardiographic Assessment in Patients with Selected Monomicrobial…¶
Harrison's 22e, p.1041
| BLOOD CULTURE ISOLATE | ||
|---|---|---|
| S. AUREUSa | E. FAECALISb | NON-a-HEMOLYTIC STREPTOCOCCIc |
| Intracardiac device | Symptoms ≥7 days | Symptoms ≥7 days |
| Emboli | ||
| Injection drug use | ≥2 positive cultures | One species: S. gallolyticus, S. sanguinis, S. mutans (not S. anginosus) |
| Unknown origin (no focus) |
||
| Meningitis | Heart murmur | Heart murmur |
| Preexisting valve disease (including prior endocarditis or valve prosthesis) |
||
| Vertebral osteomyelitis | ||
| Nonnosocomial health care associated (including hemodialysis) |
TABLE 133-5 Antibiotic Treatment for Infective Endocarditis Caused by Common Organisms a ORGANISM(S) Streptococci…¶
Harrison's 22e, p.1043
| ORGANISM(S) | DRUG (DOSE, DURATION) | COMMENTS |
|---|---|---|
| Streptococci | For PVE 6-week regimens are preferred. | |
| Penicillin-susceptible streptococci, S. gallolyticus (MIC ≤0.12 μg/mL) |
• Penicillin G (2–3 mU IV q4h for 4 weeks) | Can use ampicillin or amoxicillin (2 g IV q4h) if penicillin is unavailable. |
| • Ceftriaxone (2 g once daily for 4 weeks) | Can use ceftriaxone in patients with nonimmediate penicillin allergy. | |
| • Vancomycinb (15 mg/kg IV q12h for 4 weeks) | Use vancomycin for patients with immediate (urticarial) or severe penicillin allergy. Obtain allergy consultation for further evaluation including role of β-lactam desensitization. |
|
| • Penicillin G (2–3 mU IV q4h) or ceftriaxone (2 g IV once daily) for 2 weeks plus Gentamicinc (3 mg/kg daily IV or IM, as a single dosed for 2 weeks) |
Can use ampicillin or amoxicillin (2 g IV q4h) if penicillin is unavailable. Avoid 2-week regimen when risk of aminoglycoside toxicity is increased and in prosthetic-valve or complicated endocarditis. Penicillin G at a dose of 4 mU IV q4h or ceftriaxone 2 g once daily for 6 weeks both with or without gentamicin during the initial 2 weeks preferred for PVE caused by streptococci with penicillin MICs ≤0.12 μg/mL. |
|
| Relatively penicillin-resistant streptococci, S. gallolyticus (MIC >0.12 μg/mL and <0.5 μg/mLe) |
• Penicillin G (4 mU IV q4h) or ceftriaxone (2 g IV daily) for 4 weeks plus Gentamicinc (3 mg/kg daily IV or IM, as a single dosed for 2 weeks) |
Can use ampicillin or amoxicillin (2 g IV q4h) if penicillin is unavailable. Penicillin G at a dose of 4 mU IV q4h or ceftriaxone 2 g once daily for 6 weeks both with gentamicin during the initial 2 weeks preferred for PVE caused by streptococci with penicillin MICs >0.12 μg/mL. |
| • Vancomycinb as noted above for 4 weeks | Use vancomycin for patients with immediate (urticarial) or severe penicillin allergy. Obtain allergy consultation for further evaluation including role of β-lactam desensitization. Ceftriaxone alone or with gentamicin can be used in patients with nonimmediate β-lactam allergy. |
|
| Moderately penicillin-resistant streptococci (MIC, ≥0.5 μg/mL and <8 μg/mL); Granulicatella, Abiotrophia, or Gemella spp. |
• Penicillin G (4–5 mU IV q4h) or ceftriaxone (2 g IV daily) for 6 weeks plus Gentamicinc (3 mg/kg daily IV or IM in 2–3 equally divided doses for 6 weeks) |
Can use ampicillin or amoxicillin (2 g IV q4h) if penicillin is unavailable. |
| • Vancomycinb as noted above for 6 weeks | Regimen is preferred by some. | |
| Enterococcie | For PVE, 6-week regimens are preferred. | |
| • Ampicillin (2 g IV q4h) plus ceftriaxone (2 g IV q12h), both for 6 weeks |
||
| • Penicillin G (4–5 mU IV q4h) for 4–6 weeks plus gentamicinc (3 mg/kg daily IV or 1 mg/kg IV q8h) for 2–6 weeks |
||
| • Ampicillin (2 g IV q4h) for 4–6 weeks plus gentamicinc (3 mg/kg daily IV or 1 mg/kg IV q8h) for 2–6 weeks |
||
| • Vancomycinb (15 mg/kg IV q12h) for 6 weeks plus gentamicinc (3 mg/kg daily IV or 1 mg/kg IV q8h) for 2–6 weeks |
||
| Staphylococci (S. aureus and coagulase-negative) | ||
| MSSA infecting native valves (no foreign devices) including complicated right-sided and left-sided endocarditis. |
• Nafcillin, oxacillin, or flucloxacillin (2 g IV q4h for 4–6 weeks) |
Addition of gentamicin is not recommended. For uncomplicated right-sided endocarditis, a 2-week course may be effective (see text). |
| • Cefazolin (2 g IV q8h for 4–6 weeks) | Can use cefazolin regimen for patients with nonimmediate penicillin allergy; see text regarding cefazolin vs antistaphylococcal penicillin as primary therapy. Addition of gentamicin not recommended. |
|
| • Vancomycinb (15 mg/kg IV q12h for 4–6 weeks) |
Only use vancomycin for patients with immediate (urticarial) or severe penicillin allergy until allergy consultation can be obtained for β-lactam desensitization evaluation; addition of gentamicin not recommended. |
|
| MRSA infecting native valves (no foreign devices) |
• Vancomycinb (15 mg/kg IV q8–12h) or daptomycin (8–10 mg/kg daily) for 4–6 weeks |
No role for routine use of rifampin (see text). For daptomycin treatment, see text. |
| MSSA infecting prosthetic valves |
• Nafcillin, oxacillin, or flucloxacillin (2 g IV q4h for 6–8 weeks) plus Gentamicinc (1 mg/kg IM or IV q8h for 2 weeks) plus • Rifampinf (300 mg PO q8h for 6–8 weeks) |
Use gentamicin during initial 2 weeks; determine gentamicin susceptibility and await blood culture clearance before initiating rifampin (see text); if patient is highly allergic to penicillin, use regimen for MRSA and obtain allergy consultation; if β-lactam allergy is of the minor nonimmediate type, cefazolin can be substituted for oxacillin, nafcillin, or flucloxacillin. |
| MRSA infecting prosthetic valves |
• Vancomycinb (15 mg/kg IV q12h for 6–8 weeks) plus Gentamicinc (1 mg/kg IM or IV q8h for 2 weeks) plus • Rifampinf (300 mg PO q8h for 6–8 weeks) |
Use gentamicin during initial 2 weeks; determine gentamicin susceptibility and await blood culture clearance before initiating rifampin (see text). Daptomycin (8–10 mg/kg daily) is an alternative to vancomycin. |
TABLE 133-6 Indications for Cardiac Surgical Treatment in Patients with Endocarditis Surgery Required for Optimal…¶
Harrison's 22e, p.1046
- Surgery Required for Optimal Outcome
- Native-valve or prosthetic-valve endocarditis
- Moderate or severe congestive heart failure or shock due to valve dysfunction
- Paravalvular extension of infection with abscess, fistula, or heart block
- Persistent bacteremia without an extracardiac cause despite 7–10 days of
optimal antimicrobial therapy - Lack of effective antimicrobial therapy (e.g., fungal [see text regarding
Candida spp.], Brucella, multidrug-resistant gram-negative bacillary
endocarditis) - Prosthetic-valve endocarditis
- Partially dehisced unstable prosthetic valve
- Surgery to Be Strongly Considered for Improved Outcomea
- Prosthetic-valve endocarditis
- S. aureus infection with intracardiac complications
- Relapse after optimal antimicrobial therapy
- Native-valve endocarditis
- Large (>10-mm) hypermobile vegetation, particularly with prior systemic
embolus and significant valve dysfunctionb - Very large (>30-mm) vegetation
- Persistent unexplained fever (≥10 days) in blood culture–negative endocarditis
- Poorly responsive or relapsed endocarditis due to highly antibiotic-resistant
enterococci or gram-negative bacilli
TABLE 133-7 Timing of Cardiac Surgical Intervention in Patients with Endocarditis TIMING Emergent (same day)¶
Harrison's 22e, p.1046
| TIMING | INDICATION FOR SURGICAL INTERVENTION | |
|---|---|---|
| STRONG SUPPORTING EVIDENCE | CONFLICTING EVIDENCE, BUT MAJORITY OF OPINIONS FAVOR SURGERY |
|
| Emergent (same day) | Valve dysfunction with pulmonary edema or cardiogenic shock Acute aortic regurgitation plus preclosure of mitral valve |
|
| Sinus of Valsalva abscess ruptured into right heart | ||
| Rupture into pericardial sac | ||
| Valve obstruction by vegetation Unstable (dehisced) prosthesis Acute aortic or mitral regurgitation with heart failure (New York Heart Association class III or IV) Septal perforation Paravalvular extension of infection with or without new electrocardiographic conduction system changes Lack of effective antibiotic therapy |
||
| Elective (earlier usually preferred) |
Progressive paravalvular prosthetic regurgitation Valve dysfunction plus persisting infection after ≥7–10 days of antimicrobial therapy Fungal (mold) endocarditis |
Staphylococcal prosthetic-valve endocarditis with intracardiac complications Early prosthetic-valve endocarditis (≤2 months after valve surgery) Candida spp. endocarditis (see text) |
| Antibiotic-resistant organisms |
TABLE 133-8 Antibiotic Regimens for Prophylaxis of Endocarditis in Adults with High-Risk Cardiac Lesions a,b A.…¶
Harrison's 22e, p.1048
- A. Standard oral regimen
- Amoxicillin: 2 g PO 1 h before procedure
- B. Inability to take oral medication
- Ampicillin: 2 g IV or IM within 1 h before procedure
- C. Penicillin allergy
-
- Cephalexinc: 2 g PO 1 h before procedure
-
- Clarithromycin or azithromycin: 500 mg PO 1 h before procedure
-
- Doxycycline: 100 mg PO 1 h before procedure
- D. Penicillin allergy, inability to take oral medication
- Cefazolinc or ceftriaxonec: 1 g IV or IM 30 min before procedure
TABLE 133-9 High-Risk Cardiac Lesions for Which Endocarditis Prophylaxis Is Advised Before Dental Procedures Prosthetic…¶
Harrison's 22e, p.1048
- Prosthetic heart valves or material
- Left ventricular assist devices or implantable heart
- Prior endocarditis
- Unrepaired cyanotic congenital heart disease, including palliative shunts or
conduits - Completely repaired congenital heart defects during the 6 months after repair
- Repaired congenital heart disease with residual defects adjacent to prosthetic
material - Surgical or transcatheter pulmonary artery valve or conduit placement
- Valvulopathy developing after cardiac transplantation